Can't connect to FTP

[kampi]

Hello,

Since last week I can't connect to a FTP Server. I tried it from 3 PCs. Two of them is Windows 10 1909 with current updates and TC 9.51. From both PC the connection is not possible. Using FileZilla however works. The third PC is Windows 10 1903 with TC 9.22. From this PC the connection is working fine. So I don't know if it is a TC problem or a windows update caused this.
The FTP logfile is below (some information omitted)

Code: Select all

----------
Using sChannel (Secur32.dll) for SSL/TLS connection.
Connect to: (2020.05.06 13:49:06)
hostname=****
username=***
startdir=****
********
220-Willkommen auf dem FTP Server von ****
220-Wir empfehlen zum Verbinden einen FTP(S) Client
220-z.B.: Filezilla oder WinSCP.
220-Bitte stellen Sie sicher, dass ihre Firewall
220-ausgehend verschluesselte Verbindungen
220 auf dem Port 21 oder 990 zulaesst.
AUTH TLS
234 Using authentication type TLS
Using client certificate...
Method: TLSv1.2
Cert subject: CN=***** C=DE, O=*****
Cert issuer: CN=****, C=DE, O=*****
USER ****
331 Password required for ****
PASS ******
230 Logged on
SYST
215 UNIX emulated by FileZilla
FEAT
211-Features:
 MDTM
 REST STREAM
 SIZE
 MLST type*;size*;modify*;
 MLSD
 AUTH SSL
 AUTH TLS
 PROT
 PBSZ
 UTF8
 CLNT
 MFMT
 EPSV
 EPRT
211 End
PBSZ 0
200 PBSZ=0
PROT P
200 Protection level set to P
CLNT Total Commander (UTF-8)
200 Don't care
OPTS UTF8 ON
202 UTF8 mode is always enabled. No need to send this command.
CWD *******
250 CWD successful. "******" is current directory.
Connect ok!
Get directory
TYPE A
200 Type set to A
PASV
227 Entering Passive Mode (******)
Connected to PASV port
MLSD
150 Opening data channel for directory listing of "******"
Data handshake failed: -2146893052
ABOR
QUIT
221 Goodbye

The error is always the same: Data handshake failed: -2146893052
Does someone has any idea how to solve this?

Thanks!

[Dalai]

Well, try with the same TC version on all PCs and you'll have your answer.

IIRC, MS broke something related to SChannel in some Windows update some time ago, although I don't know if they've fixed in the meantime.

Regards
Dalai

[sqa_wizard]

To overcome the SChannel problems of Windows: Just use the recommended OpenSSL dlls

[ghisler(Author)]

Your server must have turned on SSL session re-use. This is unfortunately no longer supported by the Microsoft dlls, they completely removed it with a recent "security" update. So eith do what sqa_wizard suggests, or turn off SSL session re-use on the server.

[kampi]

Thank you! sqa_wizards suggestion really worked.